The overall goal of the Epidemiology, Data Management and Biostatistics Core is to provide consultative expertise in study design, execution, data management and analysis to Center members and pilot study investigators who are planning or conducting such research in the context of the Center for Environmental Health in Northern Manhattan. The aims of this core are: 1) To consult with investigators planning or conducting center related research on issues related to study design and execution. These studies need not be limited to observational epidemiologic studies. Clinical and basic science studies also require expertise in, for example, the design of data collection instruments, the possible role of biases and issues related to the measurement of exposure, covariates, confounders and outcomes. 2) To develop a data management capacity, led by a skilled systems programmer. Services to be provided include advice on data management and analysis software, and computer hardware. Additionally, these resources would aid investigators in the initial design of computer databases, provide training to investigators and their staff, and provide trouble shooting for problems which may arise during the course of a study. 3) To consult with investigators regarding appropriate methods of data analysis. Such consultations could range from advice on simple statistical testing for randomized clinical trials to sophisticated multivariate regression models such as Poisson, proportional hazards and polychotomous logistic regression. Consultations will also be provided for methods for advanced statistical analysis, including the development of new statistical models, if required. In addition, consultation on the various methods of correction for measurement error will be provided.